<?php
header('Content-type:text/html;charset=uft-8');
function getFileExt($path){
    $ext=substr($path,strrpos($path,'.')+1);
    return $ext;
}
$path='C:\images\apple.jpg';
$ext=getFileExt($path);
echo "<p>文件路径：$path</p>";
echo "<p>文件后缀：$ext</p>";
/**
 * Created by PhpStorm.
 * User: lijifeng
 * Date: 2016/10/31
 * Time: 12:38
 */